support memset on 128bit integers

Author: brody2consult

crates/rustc_codegen_spirv/src/builder/builder_methods.rs

@@ -308,6 +308,11 @@ fn memset_fill_u64(b: u8) -> u64 {
         | ((b as u64) << 56)
 }
 
+fn memset_fill_u128(b: u8) -> u128 {
+    let b64 = memset_fill_u64(b) as u128;
+    b64 | b64 >> 64
+}
+
 fn memset_dynamic_scalar(
     builder: &mut Builder<'_, '_>,
     fill_var: Word,
@@ -387,6 +392,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 64 => self
                     .constant_u64(self.span(), memset_fill_u64(fill_byte))
                     .def(self),
+                128 => self
+                    .constant_u128(self.span(), memset_fill_u128(fill_byte))
+                    .def(self),
                 _ => self.fatal(format!(
                     "memset on integer width {width} not implemented yet"
                 )),
@@ -402,6 +410,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 64 => self
                     .constant_i64(self.span(), memset_fill_u64(fill_byte) as i64)
                     .def(self),
+                128 => self
+                    .constant_u128(self.span(), memset_fill_u128(fill_byte))
+                    .def(self),
                 _ => self.fatal(format!(
                     "memset on integer width {width} not implemented yet"
                 )),

crates/rustc_codegen_spirv/src/codegen_cx/constant.rs

@@ -50,6 +50,10 @@ impl<'tcx> CodegenCx<'tcx> {
         self.constant_int_from_native_unsigned(span, val)
     }
 
+    pub fn constant_u128(&self, span: Span, val: u128) -> SpirvValue {
+        self.constant_int_from_native_unsigned(span, val)
+    }
+
     fn constant_int_from_native_unsigned(&self, span: Span, val: impl Into<u128>) -> SpirvValue {
         let size = Size::from_bytes(std::mem::size_of_val(&val));
         let ty = SpirvType::Integer(size.bits() as u32, false).def(span, self);

tests/compiletests/ui/lang/core/array/init_array_i128.rs

@@ -0,0 +1,14 @@
+// build-pass
+
+use spirv_std::spirv;
+
+pub fn u128_constant() -> [u128; 4] {
+    return [0x123456789ABCDEF0123456789ABCDEF; 4];
+}
+
+pub fn i128_constant() -> [i128; 4] {
+    return [0x123456789ABCDEF0123456789ABCDEF; 4];
+}
+
+#[spirv(fragment)]
+pub fn main() {}

tests/compiletests/ui/lang/core/array/init_array_i128_zeroed.rs

@@ -0,0 +1,20 @@
+// build-pass
+
+use spirv_std::spirv;
+
+/// `crypto-common` has a proc macro to implement code for u8, u16, u32, u16 and u128, which means we need our codegen
+/// to handle the u128 case for the crate to even compile. Specifically, this calls `memset_const_pattern` with u128.
+///
+/// Note that the u128 path is unusable anyway as 128bit integer are not supported in SPIR-V. So if this is used nowhere
+/// in any entry point, our post-link DCE will remove the u128 code and the SPIR-V will be valid.
+/// <https://github.com/RustCrypto/traits/blob/f896a76d4468f1ff855b651124fd5b5378a3417f/crypto-common/src/hazmat.rs#L61-L83>
+pub fn u128_zero_fill() -> [u128; 4] {
+    return [0; 4];
+}
+
+pub fn i128_zero_fill() -> [i128; 4] {
+    return [0; 4];
+}
+
+#[spirv(fragment)]
+pub fn main() {}